In general, in an excavator, a work implement including a bucket is driven by an operator operating operating levers. At this time, when a slope with a predetermined inclination, a ditch with a predetermined depth, or the like, is excavated, it is difficult for the operator to determine whether excavation is properly performed just as a target shape, only by visually checking the operation of the work implement. In addition, the operator requires a skill to become able to efficiently and properly excavate such a slope with the predetermined inclination just as the target shape. Hence, for example, there is a technique for assisting the operator by displaying position information of the bucket located at the tip of the work implement, on a display apparatus. For example, Patent Literature 1 describes that a facing compass is displayed as an icon indicating the direction of facing a target plane and the direction in which an excavator is to swing.